摘要:

ABSTRACTThis paper describes the cortical anatomy and development of mirror‐image doublets ofStylonychia mytilus, analyzed using the protargol technique. The reversed, or “left‐handed” (LH) component of these doublets is a mirror image of the normal or “right handed” (RH) component with regard to the arrangement of cortical structures. The mirror‐image patterning is imperfect, however, as the individual ciliary structures of the LH component all are of normal internal asymmetry, and the orientation of membranelles is inverted. Certain structures that would be expected to form near the line of symmetry are absent. During cell division and cortical reorganization, ciliary primordia arise and become arranged in a mirror‐image pattern that is more perfect than that exhibited by the mature structures. Deviations from a mirror‐image pattern appear at late stages when organelle sets differentiate within ciliary primordia: for example, the membranelle set differentiates within the oral primordium of the LH component in a sequence that is an inversion rather than a mirror image of the corresponding sequence of the RH component. This mixed control of oral development by different cortical “informational systems” accounts for some of the characteristic abnormalities of the mature oral structure

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01106.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTMirror‐image doublets of Stylonychia mytilus include 2 sets of cortical structures, one with the normal “right‐handed” (RH) arrangement, the other with a reversed “left‐handed” (LH) arrangement. These sets, however, are incomplete, with certain structures, most notably cirri of the right marginal type, missing near the line of symmetry. When a mirror‐image doublet is bisected longitudinally to separate the RH and LH components physically, each fragment undergoes a regeneration process that restores a complete set of cortical structures, including the previously missing cirri of the right marginal type. In the resulting LH cell, all ciliary structures are present in an arrangement that is globally reversed in relation to that found in RH cells; in particular, marginal cirri of the left‐marginal type are formed at the cell's right margin, and marginal cirri of the right‐marginal type are produced at the cell's left margin. Whereas the regenerated RH fragment always divides and initiates a clone of normal singlets, the LH fragment, though structurally nearly complete, in all cases eventually dies without dividing. The cause of death is starvation due to the formation of an abnormal oral apparatus. In the Discussion, we consider the nature and consequences of a reversal of global pos

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01107.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTGametogenesis in the foraminiferCribrothalammina albainvolves changes in both the gamontic test and cytoplasm. As gametes begin to differentiate and gametic flagella emerge, pores form in a regular array over the gamontic test, constituting the only avenue for gamete release. The spherical, biflagellated gametes average 1.5μ in diameter and are released in rapidly moving swarms along with flagellated “spherical masses” that probably result from incomplete gametic differentiation. Gametogenesis occurs entirely within the test and utilizes the entire cytoplast. After gamete release is complete, the agglutinated test collapses and disaggregates within a fairly short time. Similar modifications of the gamontic test occur during gametogenesis inOvammina opacaDahlgren, but are otherwise unknown among monothalamous agglutinated foraminifera at pre

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01108.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTThe ultrastructure ofTrypanosoma brucei gambiensewas investigated by the freeze‐fracture method. Three different regions of the continuous plasma membrane; cell body proper, flagellar pocket, and flagellum were compared in density and distribution of the intramembranous particles (IMP's). The IMP‐density was highest in the flagellar pocket membrane and lowest in flagellum. Intra membranous particles of the cell body membrane were distributed uniformly on both the protoplasmic (P) and exoplasmic (E) faces. On the P face of the flagellar membrane, a single row of IMP‐clusters was seen along the juncture of the flagllum to the cell body. Since the spacing of the IMP‐clusters was almost equal to the spacing of the paired rivet structures observed in thin section, these clusters likely are related to the junction of flagellum and cell body. At the neck of the flagellar pocket, several linear arrays of IMP's were found on the P face of the flagellar membrane, while on the E face rows of depressions were seen. At the flagellar base, the clusters of IMP's were only seen on the P face. On the flagellar pocket membrane, particle‐rich depressions and linear particle arrays were also found on the P face, while on the E face such special particle arrangements were not recognized. These particle‐rich depressions may correspond to the sites of pinocytosis of the bloodstream forms which have been demonstrated in th

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01109.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTMethods for inducing selfing, and the relation between selfing and the life cycle ofEuplotes woodruffisyngen 3 are reported. Three intercrossing stocks were used in this experiment. Selfing was induced with several treatments as follows: cell‐free fluid from the cultures of complementary mating types; intact cells of GI or S phase in the cell cycle; heat‐killed cells, and lysed cells of GI‐, S‐, and D‐phase cells which were prepared by freeze‐thawing. Stock SJ‐27 was used as a parental stock from which Fl clones were originated through selfing. The other two stocks, SJ‐8 and SJ‐19, were used as testers. The period of immaturity varied from clone to clone. The heterotypic conjugation of clones with cells of stock SJ‐8 seems to occur earlier in the life cycle than with cells of stock SJ‐19. This result shows that this syngen has an adolescent period in the life cycle. The length of selfing immaturity seems to be different from that of crossing immaturity, and selfing appeared slightly later than crossing with testers. But the clones in which selfing 1st occurred are considered to be in adolescence or maturity, not in senility. Once selfing appeared in any clone, the clone continued to produce selfing pairs till just before clonal death. The viability of selfing and of outcrossing were compared and found not significantly different. Inbreeding depression took place in some of the F2 clones by successive selfing. The viability of F2 clones from young parents was significantly higher than that from old parents (220 to 230 fissions) both in selfing and outcrossing. The total life spans which were studied in three F1 clones wer

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01110.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTTrypanosoma (Megatrypanum) freitasi, a parasite of didelphid opossum, was known to be very difficult to cultivate in conventional media. Co‐cultivation with L929 cell line in Baltz's medium at 27.5° C resulted in luxuriant growth of the trypanosome with the production of epimastigote colonies that adhered to the surface of culture flasks or tubes, and transformation into metacylics. Further transformation was stimulated by raising the incubation temperature. At 37° C the population was of the bloodstream type and resistant to lysis by complem

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01111.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTTrypanosoma (Megatrypanum) freitasi, a parasite of marsupials of the genusDidelphis, has been found to undergo in the lumen of the scent (anal) glands of its vertebrate host, a cycle such as usually occurs in the intestinal tract of the insect vectors of trypanosomatids and similar to what has been reported forTrypanosoma (Schizotrypanum) cruzi.The invertebrate host ofTrypanosoma freitasiis still unknown. Developmental stages of the trypanosome in its mammalian host, especially the dividing epimastigotes, multinucleate plasmodial forms and rosettes found in the lumen of the scent glands of a naturally infectedDidelphis marsupialisare described and illustrated.

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01112.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTWe describe how to obtain an increased merozoite invasion ofPlasmodium falciparuminto human erythrocytes during short periods of time. Using this procedure, infected erythrocytes show multiple invasions (2–4 merozoites per erythrocyte), amplifying, several times, the effects of parasite entry into host cells. The procedure yields synchronous cultures (2‐h age range) with parasitemia as high as 15%. It is possible to reach parasitemia of 50% or higher allowing for a 6‐h invasion p

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01113.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTOrtholinea alatan. sp. is described from the northern butterfly fish,Chaetodon rainfordicollected at Heron Island, Great Barrier Reef, Australia. Spherical, disporous trophozoites (10–15 μ) and spores were observed in the lumina of kidney tubules and collecting ducts. Spores are broadly triangular with two short, broad processes that extend dorsoventrad from the posterior end of each of the two spore valves. Valves are bisected by a suture in the plane of the polar capsules. Spores are 12.6 μ (length) × 9.6 μ (width) × 9.9 μ (length), and at the anterior end contain two spherical, divergent polar capsules measuring 4.6 (4.1–5.1) μ. Sporogenesis is similar to that of renalSphaerosporaspp.: the intraluminal trophozoites ofO. alatan. sp. correspond to pseudoplasmodia described forSphaerosporaspp. and no large, multinucleate plasmodia are formed. No significant histopathological changes were observed in the kidneys of inf

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01114.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

ABSTRACTFeces from a specimen ofTamandua tetradactyla(Linn.) from Portel, Para State, north Brazil, contained two different coccidial oocysts; one identified asEimeria tamanduaeLainson 1968, and the other as a new species, described here asEimeria corticulatan. sp. Oocysts ofE. corticulataare ellipsoidal, 37.4 × 30.4 (31.2–43.7 × 23.7–35.0) μm, shape index (length/width) 1.2 (1.0–1.5). Oocyst wall 2.5–3.7 μm thick and composed of two layers; an outer thick, brown‐yellow one with radial striations, and a thin inner smooth one: no visible micropyle. Oocyst residuum a large globule of about 10.7 × 10.3 μm, usually accompanied by a number of smaller attached globules. Sporocysts ellipsoidal, 21.0 × 11.0 (20.0–22.5 × 10.0–12.5) μm, with a conspicuous Stieda body: shape index 1.9 (1.6–2.2). Sporocyst residuum a small number of scattered granules: sporozoites 18.7 × 5.0 μm, with a large posterior refractile body.Eimeria zygodontomyisn. sp. is described in feces from Zygodontomys lasiurus (Lund) from the Serra dos Carajas, Para. Oocysts ellipsoidal to cylindrical, 16.5 × 12.0 (13.7–18.7 × 11.2–12.3) μm, shape index 1.4 (1.2–1.5). Wall colorless, smooth, single‐layered and about 0.6 μm thick: no micropyle. No oocyst residuum, but a polar granule of about 1.8 × 1.0 μm is sometimes present. Sporocysts ellipsoidal, 8.4 × 5.5(7.5–8.7 × 5.0–6.2) μm, shape index 1.5 (1.4–1.7), with a thin colorless wall and a delicate Stieda body. Sporozoites

ISSN:0022-3921    

DOI:10.1111/j.1550-7408.1990.tb01115.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY